CD4(+)CD25(+) regulatory T (T(reg)) cells have a crucial role in maintaining immune tolerance. Mice and humans born lacking T(reg) cells develop severe autoimmune disease, and depletion of T(reg) cells in lymphopenic mice induces autoimmunity. Interleukin (IL)-2 signaling is required for thymic development, peripheral expansion and suppressive activity of T(reg) cells. Animals lacking IL-2 die of autoimmunity, which is prevented by administration of IL-2-responsive T(reg) cells. In light of the emerging evidence that one of the primary physiologic roles of IL-2 is to generate and maintain T(reg) cells, the question arises as to the effects of IL-2 therapy on them. We monitored T(reg) cells during immune reconstitution in individuals with cancer who did or did not receive IL-2 therapy. CD4(+)CD25(hi) cells underwent homeostatic peripheral expansion during immune reconstitution, and in lymphopenic individuals receiving IL-2, the T(reg) cell compartment was markedly increased. Mouse studies showed that IL-2 therapy induced expansion of existent T(reg) cells in normal hosts, and IL-2-induced T(reg) cell expansion was further augmented by lymphopenia. On a per-cell basis, T(reg) cells generated by IL-2 therapy expressed similar levels of FOXP3 and had similar potency for suppression compared to T(reg) cells present in normal hosts. These studies suggest that IL-2 and lymphopenia are primary modulators of CD4(+)CD25(+) T(reg) cell homeostasis.

Background The objective of this study was to characterize the clinicopathologic features of sicca syndrome associated with immune checkpoint inhibitor (ICI) therapy. Subjects, Materials, and Methods Consecutive patients with new or worsening xerostomia in the setting of ICI treatment for benign or malignant neoplastic disease were evaluated, including labial salivary gland biopsy (LSGB). Results Twenty patients (14 male; median age 57 years) had metastatic melanoma (n = 10), metastatic carcinoma (n = 6), or recurrent respiratory papillomatosis (n = 4) and were being treated with avelumab (n = 8), nivolumab (n = 5), pembrolizumab (n = 4), nivolumab/ipilimumab (n = 2), and M7824, a biologic targeting programmed cell death ligand 1 (PD‐L1) and transforming growth factor ß (n = 1). Four had pre‐existing autoimmune disease. Nineteen had very low whole unstimulated saliva flow; six had new dry eye symptoms. The median interval between ICI initiation and dry mouth onset was 70 days. Rheumatoid factor and anti‐Sjögren's Syndrome‐related Antigen A (Anti‐SSA) were both positive in two subjects. LSGB showed mild‐to‐severe sialadenitis with diffuse lymphocytic infiltration and architectural distortion. There were lymphocytic aggregates in eight patients, composed mainly of CD3+ T cells with a slight predominance of CD4+ over CD8+ T cells. ICI targets (e.g., programmed cell death 1 and PD‐L1) were variably positive. In direct response to the advent of the sicca immune‐related adverse event, the ICI was held in 12 patients and corticosteroids were initiated in 10. Subjective improvement in symptoms was achieved in the majority; however, salivary secretion remained very low. Conclusion ICI therapy is associated with an autoimmune‐induced sicca syndrome distinct from Sjögren's syndrome, often abrupt in onset, usually developing within the first 3 months of treatment, and associated with sialadenitis and glandular injury. Improvement can be achieved with a graded approach depending on severity, including withholding the ICI and initiating corticosteroids. However, profound salivary flow deficits may be long term. Implications for Practice Sicca syndrome has been reported as an immune‐related adverse event (irAE) of immune checkpoint inhibitor therapy (ICI) for neoplastic diseases. Severe dry mouth (interfering with eating or sleeping) developed abruptly, typically within 90 days, after initiation of ICI therapy. Salivary gland biopsies demonstrated mild‐to‐severe sialadenitis distinct from Sjögren's syndrome, with diffuse T‐cell lymphocytic infiltration and acinar injury. Recognition of the cardinal features of ICI‐induced sicca will spur appropriate clinical evaluation and management, including withholding of the ICI and corticosteroid, initiation. This characterization should help oncologists, rheumatologists, and oral medicine specialists better identify patients that develop ICI‐induced sicca to initiate appropriate clinical evaluation and therapy to reduce the likelihood of permanent salivary gland dysfunction.

Purpose: Patients with metastatic or recurrent Ewing's sarcoma family of tumors and alveolar rhabdomyosarcoma have <25% 5-year survival in most studies. This study administered a novel immunotherapy regimen aimed at consolidating remission in these patients. Experimental Design: Fifty-two patients with translocation positive, recurrent, or metastatic Ewing's sarcoma family of tumors or alveolar rhabdomyosarcoma underwent prechemotherapy cell harvest via apheresis for potential receipt of immunotherapy. Following completion of standard multimodal therapy, 30 patients ultimately initiated immunotherapy and were sequentially assigned to three cohorts. All cohorts received autologous T cells, influenza vaccinations, and dendritic cells pulsed with peptides derived from tumor-specific translocation breakpoints and E7, a peptide known to bind HLA-A2. Cohort 1 received moderate-dose recombinant human interleukin-2 (rhIL-2), cohort 2 received low-dose rhIL-2, and cohort 3 did not receive rhIL-2. Results: All immunotherapy recipients generated influenza-specific immune responses, whereas immune responses to the translocation breakpoint peptides occurred in 39%, and only 25% of HLA-A2 + patients developed E7-specific responses. Toxicity was minimal. Intention-to-treat analysis revealed a 31% 5-year overall survival for all patients apheresed (median potential follow-up 7.3 years) with a 43% 5-year overall survival for patients initiating immunotherapy. Conclusions: Consolidative immunotherapy is a scientifically based and clinically practical approach for integrating immunotherapy into a multimodal regimen for chemoresponsive cancer. Patients receiving immunotherapy experienced minimal toxicity and favorable survival.The robust influenza immune responses observed suggest that postchemotherapy immune incompetence will not fundamentally limit this approach. Future studies will seek to increase efficacy by using more immunogenic antigens and more potent dendritic cells.Impressive advances in the last 30 years for patients with clinically localized Ewing's sarcoma family of tumors (ESFT) and alveolar rhabdomyosarcoma (AR) have led to current survival rates of 60% to 70% (1 -3). However, several clinical groups continue to fare poorly, and long-term toxicity related to therapy is substantial (4). ESFT patients who present with isolated pulmonary metastases have 5-year survival rates f30%, whereas <20% of ESFT patients with bone or bone marrow involvement at initial diagnosis survive (5 -7), and ESFT patients who recur after frontline therapy also have dismal long-term survival rates (8, 9). Similarly, 5-year survival rates among patients with newly diagnosed metastatic AR are <25% (1, 10), and of the 30% to 40% of patients who present with localized disease but relapse after frontline therapy, most will eventually die of progressive disease (9, 11). Several chemotherapy regimens have shown activity in recurrent , but none of these regimens are curative. Therefore, novel therapeutic approaches are needed to improve ...

Peptide vaccination as administered in this trial did not alter the dismal clinical outcome for patients with recurrent pediatric sarcomas. Future trials of tumor vaccines in this population should target patient populations with improved immune competence and smaller tumor burdens. Furthermore, optimization of the antigen presenting cell populations may be important for inducing immune responses to peptide antigens.